Urological stent-catheter system having varing diameter stent

ABSTRACT

A combination ureteral stent-ureteral catheter comprising an elongated flexible tubular member which has proximal and distal ends in the form of curls when present in its internalized stent form and which further comprises an elongated tubular rigid extension attached to the distal end of the stent which allows the combination to function as an externalized ureteral catheter. On extracting the rigid extension from the stent while the device is in place, the distal end of the stent reforms itself into a preformed curl and thereafter functions as a Double J internalized catheter or stent.

This is a continuation of application Ser. No. 07/704,718, filed May 20,1991, now U.S. Pat. No. 5,116,309, which is a continuation of Ser. No.07/301,090, filed Jan. 25, 1989, now abandoned.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a universal catheter inserted byconventional means which, once in place, functions as an externalureteral catheter which can be easily converted into an internalizedureteral catheter or stent.

BACKGROUND OF THE INVENTION

Ureteral catheters and stents are fundamental to the practice ofUrology. These devices allow one to bypass and drain an obstructedureter, determine urine output from a particular renal unit, and injectcontrast to study the upper urinary tract With the advent of newermethods to manage upper urinary tract stones (ESWL and ureteroscopy),the indications and use of ureteral catheters have and will continue tofurther increase.

The ideal ureteral catheter should allow one to measure urine outputfrom a particular renal unit, drain even tenaciously purulent material,allow injection of contrast for imaging and finally remain indwellingand self contained if longterm ureteral stenting or drainage isrequired.

The presently available devices consist of external or internal ureteralcatheters. Both types are usually passed through the ureteral meatus viaa cystoscope, though they can be placed openly through different sitesin the urinary tract.

Externalized ureteral catheters drain the upper urinary tract and passthrough the bladder, exiting the urethra and draining into an externalcollecting device. They allow drainage through ports and a central lumenand can be irrigated as needed to drain tenacious and obstructingmaterial By draining externally, the output from the involved renal unitcan be carefully monitored. Contrast can be injected as needed toevaluate the upper tract.

Unfortunately, these devices are not self contained and must be securedto an indwelling urethral catheter or they will migrate and be extrudedby ureteral peristalsis. They therefore are not suitable for longtermoutpatient care.

With this objective in mind, internalized ureteral catheters weredeveloped. The most commonly used type is a plastic catheter with a curlat both the proximal and distal ends; i.e. Double J catheter. The curlsare straightened over a central stiffening wire in order to pass thestent, but are reformed when the stiffening wire is removed. Theproximal curl prevents distal migration and thereby keeps the device inthe renal pelvis. The distal curl is positioned in the bladder to allowcompletely internalized drainage. No urethral catheter is needed tosecure this type of stent, making it ideal for outpatient management.

U.S. Pat. No. 4,713,049 to Carter; U.S. Pat. No. 4,307,723 to Finney andU.S. Pat. No. 4,610,657 to Densaw all show this general approach whileU.S. Pat. No. 4,531,933 shows a variation of this concept by usinghelixes to replace hooks.

The devices shown by these patents, however, have disadvantages. Theurine output from the involved renal unit can not be recorded as onlytotal urethral urine output can be recorded and this would include bothkidneys. Also, since the distal end of the catheter is internalized, itis not possible to irrigate the tube should it become obstructed. Underthese circumstances the obstructed catheter could be more detrimentalthan beneficial as it would occlude an already narrowed ureteral lumen.Since the ureteral catheter can become obstructed without any externalindication, the situation can become dramatically acute before it isrealized that the internalized stent is no longer serving its purpose.Lastly, as the stent is not externalized, contrast cannot be injected ifneeded to image the upper tract.

A modification of the usual Double J catheter is available at presentthat allows injection of contrast via a small lumen in the stiffeningwire. This lumen however, is too small to allow reliable and accuratemonitoring of urine output or drainage and irrigation of tenaciousdebris from the involved kidney.

SUMMARY AND OBJECT OF THE INVENTION

It is an object of the present invention to provide a combinationcatheter-stent that improves on the known prior art devices in that ithas the advantages of both an externalized ureteral catheter and theadvantage of an internalizable ureteral catheter once the necessity ofexternalized drainage or access is overcome.

The device of the present invention comprises a Double J catheter withside ports along its proximal half. The proximal end is preferablyclosed. The distal one-third of the Double J catheter has a wider lumendiameter and is open ended and has consequently a somewhat wider outerdiameter than the proximal end. This allows the distal end of theureteral stent to accept the insertion of a rigid open-ended ureteralcatheter. The distal end of the Double-J catheter terminates in a flangeof greater outer diameter in order to allow retraction of the stiffureteral catheter from the stent against an immobilizing abuttingdevice. This rigid ureteral catheter is long enough to exit the urethraand can be drained by an external drainage system.

When the necessity of outside drainage, contrast injection, ormonitoring no longer exists, the rigid catheter can be easilydisconnected from the flexible ureteral catheter. This allows the partof the stent in the bladder to return to its preformed curl or J shapeand then function as a prior art stent of the Double J shape.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the device as assembled for packaging.

FIG. 2 is a view of the device after insertion and with the stiffeningwire removed.

FIG. 3 is a view of the stiff pusher needed for removal of the stiffureteral catheter.

FIG. 4 is a view of the device in its internalized (stent) form afterdetachment of the rigid ureteral catheter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In a preferred embodiment as shown in the figures the ureteral catheter1 of the subject invention comprises a flexible plastic tube 2 havingapertures 3 along the proximal end 4. The apertures extend between theoutside of the catheter and the lumen 5. The catheter 1 may beconstructed from any plastic material, preferably a soft flexiblematerial provided with conventional indicating means 6 and is morepreferably formed from a radiopaque silicone or silastic material of thetype conventionally used for ureteral catheters or stents. The cathetershould be marked with conventional centimeter markings to indicate thecatheter's position

Only the proximal tip 14 of the ureteral catheter need be made ofradiopaque material but it is preferable that the entire ureteralcatheter including the flange be of radiopaque material to facilitateplacement of the device.

The distal one third 12 of the flexible plastic tube has an inside andoutside diameter wider than that of the proximal end and has a flange 7that begins about 1 centimeter proximal to the distal end. The distalend of the tube is open. A rigid open ended catheter 8 of the samediameter as the proximal end of the flexible tube is fitted through theflanged end and into the distal end of the flexible plastic tube. Therigid catheter is inserted far enough into the flexible tube to assuresecure engagement of the flexible tube. The rigid catheter is held inplace by reason of its close fit with the flexible tube. The flangedesign functions to allow the pusher 16 to disengage the rigid ureteralcatheter from the flexible tube by abutting against and immobilizing theflexible tube while the rigid ureteral tube is disengaged. The outsideflange diameter is larger than the internal diameter of the pusher. Theflange is formed of the same material as the flexible tube.

As shown in FIG. 1 a stiffening wire 9 is used to keep the flexible tubestiff while the catheter as a unit is being inserted. The stiffeningwire can be passed through a rubber stopper 10 within the distal end ofthe rigid catheter. The stopper prevents the wire from receding from thedistal end of the ureteral catheter during insertion. When the apparatushas been properly placed, withdrawing the rigid wire will also withdrawthe stopper.

Portions adjacent each of the ends 11 and 12 of the flexible tubularmember 2 are formed and set in the shape of gentle curls 13 and 14 asshown in FIG. 4. The insertion of the stiff catheter 8 into the flangedend of the flexible stent straightens the curl or J 14 and holds it instraight alignment as shown in FIG. 2.

A stiffening wire 9 straightens the device including the proximal end 11of the Double J catheter for easy insertion.

A thread or suture 15 can be attached to the distal end of the flexiblecatheter in order to allow easy removal of the device by pulling on thesuture.

The rigid ureteral catheter 8 is formed of material conventionally usedfor such catheters and is preferably a stiff polymeric material with ahard smooth surface that glides such as polytetrafluoroethylene ornylon.

The rigid ureteral catheter is marked near its distal end. With therigid ureteral tube inserted in the flexible catheter, the length ofrigid tubing between the flange and the marking 17 is equal to thelength of the "pusher" 16.

The length of the "pusher" is such that when passed over the rigidureteral catheter, the flange of the flexible tube will be abutted justas the marking on the rigid ureteral catheter is visualized. This allowsthe operator to know when the flanged end of the flexible ureteralcatheter is immobilized prior to extraction of the rigid ureteralcatheter.

The device is sterilely packaged assembled. Different sizes anddiameters can be made available with component sizes scaledappropriately. The sizes, lengths and diameters of the various elementsare those conventionally used in the art.

As an example of procedure, consider a #7 French Universal Stent. Theproximal two thirds of the catheter has a size 7 French and the distalthird of the catheter has a size 8.5 French. The distal end of thesilastic catheter has a size 9 French flange that begins 1 centimeterproximal to the distal end.

The proximal J is straightened over a 0.038 mm stiff guide wire. Thiswire also passes through a rigid plastic 7 French ureteral catheterwhich is inserted into the 8.5 French distal third of the silasticcatheter The wire exits the distal part of the rigid ureteral catheterand is held in place securely by a detachable rubber stopper.

With the wire in place, the proximal end of the J catheter isstraightened and can be inserted through a #22 French cystoscope, andpassed up in the ureteral orifice to the renal pelvis. The wire then isremoved along with the rubber stopper, allowing the proximal curl toform. The rigid ureteral catheter exits through the urethra and thesystem can be used for an immediate imaging study if needed. Tocontinuously drain the kidney (i.e. to monitor urine output, drainpurulent debris, or irrigate to free the system of purulent material)one can secure the rigid ureteral catheter to an indwelling urethralcatheter and attach the rigid ureteral catheter to an external drainagebag.

Once the patient is stable and there is no more need for externaldrainage, the stent can be internalized. The rigid catheter is thencompletely cleansed with a topical disinfectant and sterile gloves aredonned. Packaged separately is a sterile size 8.5 French "pusher"0 (openended tube) which then is lubricated and passed over the rigid ureteralcatheter until resistance is met as it abuts the flanged distal end ofthe silastic ureteral catheter. The operator will also know that theflanged distal end of the silastic ureteral catheter has been abuttedbecause the marking on the rigid ureteral catheter will be visualized.Then gently pull the rigid catheter through the pusher, holding thepusher in place. Then gently extract the pusher from the urethra. Thiswill allow the distal end of the silastic catheter to form a curl in thebladder and thereby leave a completely internalized stent. The thread orsuture can be left attached to the distal end of the silastic catheterto allow easy extraction through the urethra.

If desired, the stiffening wire can be inserted first using conventionalmeans. After cutting off the proximal tip of the stent, thestent-ureteral catheter device is passed over the wire in order toinsert the catheter combination.

Also if desired, various adapters can be secured to the external end ofthe stiff ureteral catheter in order to permit irrigation, applicationof contrast solutions to the renal cavity etc.

The thread or suture is preferably of a synthetic polymer with opaquecharacteristics. It is attached to the stent at any convenient location.

The advantages of the above described device are many. The materials ofconstruction are conventional. The device can be packaged intact andready to insert. The various elements can be formed in a variety ofsizes, lengths and diameters with component sizes scaled appropriately.

The device obviates the need for separate externalized and internalizedureteral catheters. Further, the device is simple in operation and makesuse of concepts and designs proven to be effective and reliable.

The device as described in the preferred embodiment specifies insertionof the rigid catheter into the distal third of the flexible tube.However, it is only necessary that the rigid tube be held securely inthe stent until it is removed. Further, it can be seen that the specifictype of connection described is not critical. Any method of connectionthat allows the apparatus to function as described is contemplated.Also, as described, the flange, in connection with the stiff pusher,serves only to hold the apparatus in place while the stiff catheter isremoved. Any structure that serves to prevent the catheter from beingpulled out of the renal cavity when the stiff catheter is removed iscontemplated.

It will be readily apparent to those skilled in the art that a number ofmodifications and changes can be made without departing from the spiritof the invention. Therefore, it is to be understood that the scope ofthe invention is not to be limited by the foregoing description, butonly by the claims.

I claim:
 1. An elongated unitary, flexible tubular ureteral stent forimplantation in a ureteral meatus, comprising:a pair of preformed curlsat both ends of the stent and a fluid passage channel extendingsubstantially the entire length of said stent; a drain passage segmenthaving a plurality of drain passages connecting said channel to theoutside of said stent, said channel without said passage segment havinga first channel width, said drain passage segment having a first outerwidth, one end of said drain passage segment being closed and a portionof said passage segment forming one of said pair of preformed curls; aureteral catheter receiving segment integral and coextensive with saidpassage segment and having a second outer width, said channel extendingalong the length of said receiving segment and having a second channelwidth, said second channel and said second channel outer widths beinglarger than said first channel and said first channel outer widths,respectively, wherein the junction between said catheter receivingsegment and said drain passage segment being gradually tapered to form acontinuous, non-abrupt outer surface, a portion of said catheterreceiving segment forming the other preformed curl; and a flange formedat a free end of said catheter receiving segment, an end of said flangeforming an abutment surface, wherein the length of said drain passagesegment being about twice the length of said catheter receiving segment.2. A ureteral stent according to claim 1, further comprising a tubularcatheter, wherein said curl formed in said catheter receiving segment isstraightened by inserting said tubular catheter into said channel formedin said catheter receiving segment, and whereupon extraction of saidtubular catheter, said catheter receiving segment recurls.
 3. A ureteralstent according to claim 1, further comprising a stiffening wire,wherein said curl formed in said drain passage segment is straightenedby inserting said stiffening wire into said channel formed in said drainpassage segment, and whereupon extraction of said wire, said drainpassage segment recurls.
 4. A ureteral stent according to claim 1,further comprising a tubular catheter and a stiffening wire, whereinsaid curl formed in said catheter receiving segment is straightened byinserting said tubular catheter into said channel formed in saidcatheter receiving segment and wherein said curl formed in said drainpassage segment is straightened by inserting said stiffening wirethrough said catheter and into said channel formed in said drain passagesegment, and whereupon extraction of said wire, said drain passagesegment recurls and whereupon extraction of said catheter, said catheterreceiving segment recurls.
 5. A ureteral stent according to claim 1,wherein at least said drain passage segment of said stent is formed of aradiopaque material.
 6. A ureteral stent according to claim 1, whereinsaid entire stent is formed of a radiopaque material.
 7. A ureteralstent-ureteral catheter device for implantation in a ureteral meatus,comprising:an elongated unitary flexible ureteral stent having preformedset curls at both ends, said ureteral stent having a fluid passagechannel extending substantially the entire length of said stent anddrain passages formed at least over its proximal end, said drainpassages fluidly communicating said fluid passage channel to the outsideof said stent, said stent having a first outer width dimension over itsproximal two-third length and a second outer width dimension over itsdistal one-third length, said second outer width dimension being largerthan said first outer width dimension, the junction between saidproximal two-third and said distal one-third being gradually tapered sothat said first width dimension gradually changes to said second widthdimension, and a tapered flange formed at the distal end of said stent;and a rigid ureteral catheter dimensioned for inserting into said distalend of said stent to straighten the set curl formed at said distal endof said stent, wherein on extraction of said catheter from said distalend of said stent, said distal end recurls, both said curls serving toprevent migration of said stent in the ureteral meatus.
 8. A ureteralstent-ureteral catheter device according to claim 7, further comprisinga stiffening wire, wherein said curl formed in said proximal end isstraightened by inserting said stiffening wire into said channel formedin said proximal end, and whereupon extraction of said wire, saidproximal end recurls.
 9. A ureteral stent-ureteral catheter deviceaccording to claim 8, wherein said wire is dimensioned to be insertedthrough said catheter which is inserted in said distal end and into saidchannel formed in said proximal end.
 10. A ureteral stent according toclaim 7, wherein at least said proximal end of said stent is formed of aradiopaque material.
 11. A ureteral stent according to claim 7, whereinsaid entire stent is formed of a radiopaque material.
 12. A ureteralstent-ureteral catheter device for implantation in a ureteral meatus,comprising in combination:an elongated unitary flexible ureteral stenthaving preformed set curls at both ends, said ureteral stent having afluid passage channel extending substantially the entire length of saidstent and drain passage formed at least over its proximal end, saiddrain passages fluidly communicating said fluid passage channel to theoutside of said stent, said stent having a first outer width dimensionover its proximal two-third length and a second outer width dimensionover its distal one-third length ,said second outer width dimensionbeing larger than said first outer width dimension, the junction betweensaid proximal two-third and said distal one-third being graduallytapered so that said first width dimension gradually changes to saidsecond width dimension, and a tapered flange formed at the distal end ofsaid stent; a rigid ureteral catheter dimensioned for inserting intosaid distal end of said stent to straighten the set curl formed at saiddistal end of said stent; and a rigid tube having an inner width largerthan the outer width dimension of said catheter to permit said rigidtube to slide over said catheter and abut against said flange, whereinsaid rigid tube is used for extracting said catheter which is insertedinto said distal end by sliding said tube over said catheter andabutting against said flange and pulling said catheter away from saiddistal end, whereupon on extraction of said catheter from said distalend, said distal end recurls, both said curls serving to preventmigration of said stent in the ureteral meatus.
 13. A ureteralstent-ureteral catheter device according to claim 12, further comprisinga stiffening wire, wherein said curl formed in said proximal end isstraightened by inserting said stiffening wire into said channel formedin said proximal end, and whereupon extraction of said wire, saidproximal end recurls.
 14. A ureteral stent-ureteral catheter deviceaccording to claim 13, wherein said wire is dimensioned to be insertedthrough said catheter which is inserted in said distal end and into saidchannel formed in said proximal end.
 15. A ureteral stent according toclaim 12, wherein at least said proximal end of said stent is formed ofa radiopaque material.
 16. A ureteral stent according to claim 12,wherein said entire stent is formed of a radiopaque material.